语源科技BlogJava-cavenaghi

数据库连接大全!

Cavenaghi — Wed, 27 Jul 2005 07:19:00 GMT

下面的是几种常见数据库系统的数据库连接方式

系统环境:win2003 + j2se5.0 + tomcat5.5.7

前提是你已经从网上已经下载了各个数据库的JDBC支持！
把那些主要的工具包都放到Tomcat 5.5\common\lib就行！
刨除那些入门的东西吧，现在开始步入正题！
为了减少篇幅，更为了把问题说的直观，我已经把异常捕捉代码给去除了！

1.Microsoft SQL Server 2000

Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
Connection conn= DriverManager.getConnection
  ("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=数据库名字","sa","pwd");
Statement stmt=conn.createStatement();
//增加和查询语句
stmt.executeUpdate("insert into boya values('mssql','2000')");
ResultSet rs=statement.executeQuery("select * from boya");
//显示记录
while(rs.next()){
  out.print(rs.getString(1)+" "+rs.getString(2));
  out.println("
");
}

2.MySQL 5.0

Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection
  ("jdbc:mysql://localhost/数据库名字?user=root&password=pwd");
Statement stmt=conn.createStatement();
//增加和查询语句
stmt.executeUpdate("insert into boya values('mysql','5.0')");
ResultSet rs=stmt.executeQuery("select * from boya");
//显示记录
while(rs.next()){
  out.print(rs.getString(1)+" "+rs.getString(2));
  out.println("
");
}

3.PostgreSQL 8.0

//这个服务器的默认端口5432，如果更改了，代码也需要更改
Class.forName("org.postgresql.Driver");
Connection conn=DriverManager.getConnection
  ("jdbc:postgresql://localhost:5432/数据库名字?user=admin&&password=pwd");
Statement stmt=conn.createStatement();
//增加和查询语句
stmt.executeUpdate("insert into boya values('mysql','5.0')");
ResultSet rs=stmt.executeQuery("select * from boya");
//显示记录
while(rs.next()){
  out.print(rs.getString(1)+" "+rs.getString(2));
  out.println("
");
}

4.ODBC

//in my opinion 会写ODBC就够了，现在PostgreSQL、MYSQL里也都有ODBC支持,但速度慢啊!
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection conn=DriverManager.getConnection("jdbc:odbc:test","","");
Statement stmt=conn.createStatement();
//增加和查询语句
stmt.executeUpdate("insert into boya values('mysql','5.0')");
ResultSet rs=stmt.executeQuery("select * from boya");
//显示记录
while(rs.next()){
out.print(rs.getString(1)+" "+rs.getString(2));
out.println("
");
}

Cavenaghi 2005-07-27 15:19 发表评论

在JSP网页上实现月历

Cavenaghi — Wed, 27 Jul 2005 03:58:00 GMT

在JSP网页上实现月历

JSP、月历

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.util.*,java.text.*" %>

月历

<%!
/*声明变量*/
String[] months = {"January", "February", "March", "April", "May", "June",
        "July", "August", "September", "October", "November", "December"};
String[] months_cn = {"一月", "二月", "三月", "四月", "五月", "六月",
           "七月", "八月", "九月", "十月", "十一月", "十二月"};
public final static int dom[] = {
         31, 28, 31, 30,
         31, 30, 31, 31,
         30, 31, 30, 31
};
%>
<%
/*处理事件*/
boolean yyok = false;
int yy = 0, mm = 0;
String yyString = request.getParameter("year");
if (yyString != null && yyString.length() >0) {
  try {
   yy=Integer.parseInt(yyString);
   yyok=true;
  }
  catch (NumberFormatException e) {
   out.println("年份不可用");
  }
  Calendar cal = Calendar.getInstance();
  if (!yyok)
   yy = cal.get(Calendar.YEAR);
  String mmString = request.getParameter("month");
  if (mmString == null) {
   mm = cal.get(Calendar.MONTH);
  }
  else {
   for (int i = 0; i < months.length; i++)
    if (months[i].equals(mmString)) {
     mm = i;
     break;
    }
  }
}
%>

<%
int lead = 0;
%>

<% GregorianCalendar calendar = new GregorianCalendar(yy, mm ,1); %>

<%
/*下面是显示月历的代码*/
lead = calendar.get(Calendar.DAY_OF_WEEK)-1;
int dayInMonth = dom[mm];
if (calendar.isLeapYear(calendar.get(Calendar.YEAR)) && mm == 1)
  ++dayInMonth;
out.print("");
for(int i = 0; i < lead; i++) {
   out.print("");
}
for(int i = 1; i <= dayInMonth; i++) {
  if ((i+lead) % 7 == 0 || (i+lead) % 7 == 1)
   out.print("");
  else
   out.print("");
  if ((lead+i) % 7 == 0) {
   out.print("");
  }
}
out.print("");
%>

<%= months[mm]%> <%= yy%>
Sun	Mon	Tue	Wed	Thu	Fri	Sat
	"+i+"	"+i+"

Cavenaghi 2005-07-27 11:58 发表评论

递归寻求迷宫出路

Cavenaghi — Wed, 27 Jul 2005 03:54:00 GMT

迷宫文件boya.ice：

8
9
#########
#s0##0###
#0##00###
#0##0####
#0000####
#0##0####
#0##00e##
#0000####

package maze;
import java.io.*;
import java.util.*;
public class Maze{
private char[][] maze;//迷宫数组
private int startX,startY,endX,endY;//迷宫起点，终点的位置
private int x,y,step=0;//迷宫长宽及步骤
//依据输入的文件名创建对象
private Maze(String fileName){
  try{
   LinkedList aList=new LinkedList();//用于存储文件每行的内容
   BufferedReader files=new BufferedReader(new FileReader("map\\"+fileName));
   //将每行的内容依次加入到LinkedList中
   String temp=new String();
   int i=0;
   while((temp=files.readLine())!=null){
    aList.add(temp);
   }
   files.close();
   //读取并设置迷宫的长宽
   x=Integer.parseInt((String)aList.getFirst())+2;
   aList.removeFirst();
   y=Integer.parseInt((String)aList.getFirst())+2;
   aList.removeFirst();
   //依据长宽对迷宫进行初始化
   maze=new char[x][y];
   //将迷宫的赋予外围墙
   for(i=0;i    maze[i][0]='#';
    maze[i][y-1]='#';
   }
   for(i=0;i    maze[0][i]='#';
    maze[x-1][i]='#';
   }
   //将LinkedList中内容读入数组
   Iterator it=aList.iterator();
   i=1;
   char[] row;
   while(it.hasNext()){
    temp=((String)it.next());
    row=new char[y-2];
    row=temp.toCharArray();
    for(int j=1;j     maze[i][j]=row[j-1];
     if(maze[i][j]=='s'){
      startX=i;
      startY=j;
      maze[i][j]='0';
     }
     else if(maze[i][j]=='e'){
      endX=i;
      endY=j;
      maze[i][j]='0';
     }
    }
    i++;
   }
  }
  catch(FileNotFoundException e){
   System.out.println("File Name Input Wrong!!!");
  }
  catch(IOException e){
   System.out.println("Wrong Input!!!");
  }
}
//递归方法寻找路径
private boolean findWay(int x,int y){
  if(maze[endX][endY]=='i')
   return true;
  else
   if(maze[x][y]=='0'){
    maze[x][y]='i';
    if(findWay(x-1,y))
     return true;
    else if(findWay(x+1,y))
     return true;
    else if(findWay(x,y+1))
     return true;
    else if(findWay(x,y-1))
     return true;
    else{
     maze[x][y]='c';
     return false;
    }
   }
   else return false;
}
//打印迷宫路径
private void show(){
  maze[startX][startY]='s';
  maze[endX][endY]='e';
  for(int i=1;i   for(int j=1;j    if(maze[i][j]=='i'){
     maze[i][j]=' ';
     step++;
    }
    else if(maze[i][j]=='c') maze[i][j]='0';
    System.out.print(maze[i][j]);
   }
   System.out.println("");
  }
  System.out.println("I Have went "+step+" Steps To The End!");
}
public static void main(String arg[]){
  try{
   System.out.println("Boya(8*9)\n"+"Ice(10*12)\n"+"Sky(15*17)\n"+"Input the map name:");
   BufferedReader is=new BufferedReader(new InputStreamReader(System.in));
   for(;;){
    String input=new String();
    input=is.readLine().trim();
    if(input.equals("q")) break;
    else{
     Maze boya=new Maze(input+".ice");
     if(boya.findWay(boya.startX,boya.startY)){
      boya.show();
     }
     else System.out.println("No Ways to the end!");
    }
    System.out.println("Input another map name or input 'q' to quit:");
   }
   is.close();
  }
  catch(IOException e){
   System.out.println("Wrong Input!!!");
  }
  catch(NullPointerException e){
   System.out.println("Wrong Input!!!");
  }
}
}

Cavenaghi 2005-07-27 11:54 发表评论

数据结构JAVA示例---逆波兰式求值!

Cavenaghi — Wed, 27 Jul 2005 03:45:00 GMT

package expression;
public class Calculate{
public static boolean isOperator(String operator){
  if(operator.equals("+")||operator.equals("-")||operator.equals("*")||operator.equals("/")||operator.equals("(")||operator.equals(")")) return true;
  else return false;
}
public static int priority(String operator){
  if(operator.equals("+")||operator.equals("-")||operator.equals("(")) return 1;
  else if(operator.equals("*")||operator.equals("/")) return 2;
  else return 0;
}
public static String twoResult(String operator,String a,String b){
  try{
   String op=operator;
   String rs=new String();
   double x=Double.parseDouble(b);
   double y=Double.parseDouble(a);
   double z=0;
   if(op.equals("+")) z=x+y;
   else if(op.equals("-")) z=x-y;
   else if(op.equals("*")) z=x*y;
   else if(op.equals("/")) z=x/y;
   else z=0;
   return rs+z;
  }
  catch(NumberFormatException e){
   System.out.println("input has something wrong!");
   return "Error";
  }
}
}

package expression;
import java.util.*;
public class Stacks{
private LinkedList list=new LinkedList();
int top=-1;
public void push(Object value){
  top++;
  list.addFirst(value);
}
public Object pop(){
  Object temp=list.getFirst();
  top--;
  list.removeFirst();
  return temp;

}
public Object top(){
return list.getFirst();
}
}

package expression;
import java.io.*;
import java.util.*;
public class Expression{
private ArrayList expression=new ArrayList();//存储中序表达式
private ArrayList right=new ArrayList();//存储右序表达式
private String result;//结果
//依据输入信息创建对象，将数值与操作符放入ArrayList中
private Expression(String input){
  StringTokenizer st=new StringTokenizer(input,"+-*/()",true);
  while(st.hasMoreElements()){
   expression.add(st.nextToken());
  }
}
//将中序表达式转换为右序表达式
private void toRight(){
  Stacks aStack=new Stacks();
  String operator;
  int position=0;
  while(true){
   if(Calculate.isOperator((String)expression.get(position))){
    if(aStack.top==-1||((String)expression.get(position)).equals("(")){
     aStack.push(expression.get(position));
    }
    else{
     if(((String)expression.get(position)).equals(")")){
      if(!((String)aStack.top()).equals("(")){
       operator=(String)aStack.pop();
       right.add(operator);
      }
     }
     else{
      if(Calculate.priority((String)expression.get(position))<=Calculate.priority((String)aStack.top())&&aStack.top!=-1){
       operator=(String)aStack.pop();
       if(!operator.equals("(")) right.add(operator);
      }
      aStack.push(expression.get(position));
     }
    }
   }
   else right.add(expression.get(position));
   position++;
   if(position>=expression.size()) break;
  }
  while(aStack.top!=-1){
   operator=(String)aStack.pop();
   right.add(operator);
  }
}
//对右序表达式进行求值
private void getResult(){
  this.toRight();
  Stacks aStack=new Stacks();
  String op1,op2,is=null;
  Iterator it=right.iterator();
  while(it.hasNext()){
   is=(String)it.next();
   if(Calculate.isOperator(is)){
    op1=(String)aStack.pop();
    op2=(String)aStack.pop();
    aStack.push(Calculate.twoResult(is,op1,op2));
   }
   else aStack.push(is);
  }
  result=(String)aStack.pop();
  it=expression.iterator();
  while(it.hasNext()){
   System.out.print((String)it.next());
  }
  System.out.println("="+result);
}
public static void main(String avg[]){
  try{
   System.out.println("Input a expression:");
   BufferedReader is=new BufferedReader(new InputStreamReader(System.in));
   for(;;){
    String input=new String();
    input=is.readLine().trim();
    if(input.equals("q")) break;
    else{
     Expression boya=new Expression(input);
     boya.getResult();
    }
    System.out.println("Input another expression or input 'q' to quit:");
   }
   is.close();
  }
  catch(IOException e){
   System.out.println("Wrong input!!!");
  }
}
}

Cavenaghi 2005-07-27 11:45 发表评论